A throttle valve is used to control the amount of air that passes through a vaporizer or a throttle body in a vehicle. FIG. 1 illustrates a conventional throttle valve 1. The throttle valve 1 includes a valve main body 2, a flow path 8 formed in the valve main body 2 having a circular section with the center on a center line C1, (see FIG. 3) an inlet IN through which external air flows in, and an outlet OUT connected to an engine, a rotational shaft 4 rotatably coupled to the valve main body 2, a circular regulation plate 3 coupled to the rotational shaft 4 and controlling the amount of a fluid passing through the flow path 8, a lever 5 coupled to one end portion of the rotational shaft 4, a spring 7 elastically biasing the regulation plate 3 in a direction toward closing the flow path 8, and a cable 6 connected between the lever 5 and an accelerator pedal (not shown).
Accordingly, when a driver presses the accelerator pedal, the cable 6 is pulled as illustrated in FIG. 2, and the regulation plate 3 is open as illustrated in FIG. 3. When the driver does not press the accelerator pedal, the spring 7 moves the regulation plate 3 to close the flow path 8. A degree of opening of the flow path 8 by the regulation plate 3 is regulated to be proportional to a degree of the driver's pressing on the accelerator pedal.
In other words, the more the driver presses the accelerator pedal, the more the regulation plate 3 is opened, and thus, the amount of air passing through the flat path 8 increases. If the driver slightly presses the accelerator pedal, the regulation plate 3 is slightly opened, and thus, the amount of air passing through the flat path 8 decreases. When the amount of air passing through the flow path 8 increases, an electronic control unit (ECU) detects an increase in the amount of air in the flow path 8, and thus, increases an amount of fuel injected or sucked into the engine.
The occurrence of sudden unintended acceleration (SUA) accidents, which are caused as the engine rotates excessively even when the driver does not press the acceleration pedal, has recently increased. However, the conventional throttle valve 1 cannot deal with vehicle sudden unintended acceleration events.